HOMOGENEOUS AND LAYERED SAND IN TRIAXIAL COMPRESSION

Samples of Ham river sand were prepared at high and low porosities by pouring through air or a liquid, the techniques being alternated for layered samples. Some samples were reinforced with horizontal sheets of various materials. To avoid edge effects near lubricated platens in triaxial compression, strains in the middle third of each sample were recorded in accurate detail. Changing the relation of the plane of deposition to the major principal stress direction revealed inherent anisotropy effects. Stress-strain and strength data show the influence of porosity, layer geometry and horizontal reinforcing sheets. In homogeneous samples the orientation of lines of zero extension in the maximum-shear plane depended on porosity but not on current strain or inherent anisotropy. Inherent anisotropy did not affect the stress-dilatancy relationship, nor did changing its axes affect the virtual coincidence of stress and strain rate axes. But pre-failure strains were largely influenced by inherent anisotropy at both porosities and the lower porosity gave appreciable strength anisotropy. Layered samples were weaker, depending on layer geometry and the loose layers sustained large strains while at maximum stress ratio. No thin ruptures formed, but at failure the strains were confined within loose layers, when these were oriented so that a line of zero extension was parallel to their plane. This orientation differed appreciably from that of maximum stress obliquity. The stress-dilatancy relationship for homogeneous samples predicted stress ratios in both layered and reinforced samples. The loose sand dilated much more when in a layer than in homogeneous samples. (A) /TRRL/

Media Info

  • Features: Figures; Photos; References;
  • Pagination: p. 799-815
  • Serial:
    • GEOTECHNIQUE
    • Volume: 25
    • Issue Number: 4
    • Publisher: Thomas Telford Limited
    • ISSN: 0016-8505

Subject/Index Terms

Filing Info

  • Accession Number: 00134228
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Sep 4 1976 12:00AM